Crank grinding machines



May 3, 1955 H E. BALSIGER ETAL CRANK GRINDING MACHINES Original FiledAug. 26, 1948 4 Shets-Sheet 1 r w n c U n 3 Mano/.1: f. Bnwmne RALPH 5.PRICE (Ittorncg H. E. BALSIGER QETAL CRANK GRINDING MACHINES OriginalFiled Aug. 26, 1948 May 3, 1955 4 Sheets-Sheet 2 l/AROLDIZ. 541.5165?(menu-g y 3, 1955 H. E. BALSIGER ETAL Re. 23,991

CRANK GRINDING MACHINES Original Filed Aug. 26 1948 4 Sheets-Sheet 4'Jnuemon 35 /ARQLD f. fills/GEE IPALPI/ 5. Part:

United States Patent 23,991 CRANK GRINDING MACHINES Harold E. Balsiger,Waynesboro, Pm, and Ralph E. Price, Beloit, Wis asslanors to Landls ToolCompany, Wayneeboro, Pa.

Original No. 2,638,719, dated May 19, 1953, Serial No. 46,336, August26, 1948. Application for reissue May 17, 1954, Serial No. 430,468

28 Claims. (Cl. 51-105) This invention relates to grinding machines,particularly for grinding crankshafts or other work pieces havingaxially spaced portions to be ground.

In any grinding operation a high degree of accuracy is dependent on twoand sometimes three things:

1. Accurate size control.

2. Accurate feed mechanism.

3. Accurate means for supporting the work piece, particularly ingrinding axially spaced surfaces on a work piece.

A fourth requirement might be the skillful use of all of these so as toget the best results.

We prefer to use a sizing device of the so-called pneumatic type, themost recent development of which is disclosed in co-pending applicationSer. No. 773,388, filed September 11, 1947 now Patent 2,567,360 grantedSeptember 11, 1951. However, while this is probably the most accuratesizing device available, accurate size control is dependent on anaccurate feed mechanism. It was formerly thought that the slower thefinish feed, the more accurate the final size. This slow feed was alsosupposed to permit relief of deflection in the work and in the machine.However, there was found to be a mechanical or frictional limitation toextremely slow feeding movements beyond which it was impractical to go.

It was found that by keeping the slow feed within a range not affectedby these limitations; [that] inaccuracy due to lack of uniformity offeed rate can be eliminated.

In addition to this, the entire feeding movement is divided into aseries of successive size controlled reductions in feed rate. Thepurpose of this is not to eliminate deflection entirely, but to reduceit to a minimum which can be relieved during a brief size controlledspark out operation.

One of the principal obstacles to accuracy in any machining operation isdeflection or distortion. This may occur in varying degree in the work,in the machine itself, or in both. It is the result of resilience of thework piece and the machine. These parts, therefore, yield or deflectwhen forced together by the feeding mechanism. In the case of grinding,distortion or deflection of the work may be counteracted by use of aback rest.

Another obstacle to accuracy is run-out" of the work piece, that is, thecenter of the work piece and the center of rotation do not co-incide. Awork piece which is ofi center or runs-out may be perfectly round. Inorder to correct "run-out the work piece is rough ground without asteady rest and is caused to deflect by both the feeding movement andthe run-out." At a predetermined point, the wheel feed is stopped andthe work springs back toward the wheel continuing the grinding operationuntil the spring in the work is relieved. When so ground, only the sidewhich runs out is subjected to the grinding wheel at first. As therun-out" is reduced the center of the work approaches the center ofrotation until the Re. 23,991 Reissued May 3, 1955 2 two co-incide, theentire periphery of the workpiece is subjected to the grinding wheel andthe run-out" is eliminated. t

Deflection in machine parts and "run-out of the work piece may becompensated for by stopping of the feeding mechanism for the grindingwheel and permitting the deflected parts [and], assemblies and the workpiece to relieve themselves and, in so doing, to provide a spark outgrinding operation. The term spark out may be defined as a relativefeeding movement between a grinding wheel and a work piece occurringafter the feed mechanism has stopped, which is due to the relief ofstresses in the work or machine or both. These stresses are built upduring that portion of the grinding operation when the feed mechanism isoperating.

The current method of supporting crank pins during grinding is to use asingle steady rest mounted on the bed of the machine and in alignmentwith the grinding wheel. This rest moves by power into position againsta positive stop, usually as soon as the work has been ground true, andis held against said stop while the operator adjusts the position of theshoe or shoes as the work is reduced in size. The adjustment requiredfor each pin on a shaft is usually different due to unequal deflectionat various points on the shaft, and thus the steady rest must beadjusted differently for the grinding of each pin. Usually the finalincrement of stock is removed by [using] use of this adjustment to feedthe work against the wheel. This takes quite a bit of time, anduniformity of adjustment by the operator cannot be guaranteed.

We propose to use a separate steady rest for each crank pin. Each restwill be movable into work supporting position only when the pin which itis to support is in front of the grinding wheel. Each rest will bepreadjusted to the particular pin which it is to support;-i. e. when therest engages its positive stop, it is located to support that particularpin in finished size position. When moved into working position, therest will engage the work continuously until it is also engages apositive stop. When the rest engages the stop, it is deflecting worktoward wheel by a small amount. As the wheel feeds forward and the stockis removed, the work maintains contact with the rest; and as the workdiameter is reduced,

the axis of the pin coincides with the axis "of'rotationof the shaft.The adjustment of each rest should be such that, when the sizing devicestops the grinding operation, the rest still exerts enough pressure onthe workto prevent chatter. At the end of this operation which iscontrolled by the sizing device the work should be round and straightand about .0005 oversize.

The grinding operation will be stopped and the feed mechanism reseteither after a predetermined interval or by the sizing device when the.0005 stock has been removed.

It is, therefore, an object of this invention to provide a machine forgrinding crank shafts to closer limits than has been possible withprevious machines.

A further object is to provide a separate, accurately adjusted steadyrest for each of the pins of a crank shaft.

A further object is to interlock the control of the steady rest and thefeeding mechanism.

A further object is to prevent movement of any steady rest except theone for the portion of the shaft in grinding position.

A further object is to control the feeding mechanism so as to correct"run-out" of the work piece by stopping the feed mechanism during roughgrinding and starting it again after a predetermined interval.

In the drawings:

Fig. 1 is a partial plan view.

Fig. 2 is an end elevation partly in section.

Fig. 3 is an'end elevation to the steady rest operating mechanism partlyin section.

' Figure 4 is a hydraulic diagram of a safety feature of the machine. I

Figure 5 is a sectional elevation showing the relation of work restparts in operative position.

' several well-known mechanisms.

,Ihefwheel base 15 is slidably mounted on bed for ,movement ina'direction transversely of. the carriage movement. A grinding wheel 16is rotatably mounted. on

said base and driven by a motor 17 through a belt drive notshown. Said)wheel base is slidably mounted on an intermediate slide 20, which inturn is slidably mounted on bed 10. i

WHEEL FEED The means for moving wheel base toward and from the workconsists of a hydraulic motor comprising a cylinder 25 mounted on bed10, a piston 26 slidably mounted therein and having a piston rod 27connected to slide through lug '28. The dash pot mechanism 31 forcontrolling the feed movement iswell-known and will not be describedhere.- A half nut 29 on slide 20 engages a feed'screw 30 rotatablymounted in wheel base 15. 'Thus slide 20'and base 15 may be moved as aunit or base 15,, means of aging]: lever 130 Show" in Figure 4' Th:

may be moved relative to slide20, by rotation of [rotating] feed screw30.

Means for rotating feed screw 30 consists of a sprocket v .35 secured toone end of said screw, achain 36 connecting said sprocket with anothersprocket 37 on shaft 38 v I in the upper part of the base 15., .Alsomounted on said shaft 38- is a gear 39 meshing with gear 40 on handwheelshaft 41'. A handwheel 42 provides means for manually feeding base'lSalongside 20.

Handwheel 42 may be power actuated by means consisting of a cylinder'50forming part of the housing-51 I of said manual feed mechanism, having adouble-headed piston 52 slidably mounted therein. .Said'pistonconsistsoffitwo heads joined by a rack 53. Said rack engages a. pinion 54 onhandwheel shaft 41.

A limit switch on the underside of housing 51 is positioned to beactuated by a cam '62 on handwheel 42.

' This switch, when actuated, controls movement of piston 52 as. will bedescribed-later;- J A work piece in the form of a six throw crank shaftis rotatably supported on carriage ll'in hydraulicclainping fixtures 71and 72 on headstocks' not shown. 1 The details of the clamping fixturesrand head-stocksv as well asother details of machine structure aresimilar to those shown inPatent 2,220,490, granted November 5, 1940.

A separate steady rest member is provided for each of the six crank pinson crank-70. Eachsteady rest consists 'of a mainframe member 80,pivotally mounted in a base member 81 common to all six rests.Hereafter,

the numeral will be used in referring to the steady rest vas a unit. Themovement of each rest toward the work piece is limited by a stop 82located on base at in the path of movement of said frame 80. The workengaging memberis preferably a hardened shoe 83, removably mounted on asupport member 84. Said support member .is slidably mounted in saidframe 80 and. may be adjusted by means of screw 85. A tail portion 86 ontail.

- Said shaft has'ashallow transverse position.

- Before initiation of slot 89 which is engaged by a latch 96 formingone side of a recess 97 in said portion 95.

Portion is secured to the end of a piston rod 100 on piston 101. Saidpiston is slidably mounted in cylinder 102, which in turn is pivotallymounted at 103 on a bracket 104 attached'to bed 10 so they move inaccordance with the pivotal movement of the steady rest 80.

Said piston rod extends upwardly through an opening 105 in a splashguard 106[,]. Said guard is attached to a cover plate 109 which in turnis mounted on bed 10, which'extends the entire length of the work piece.Across the inside of said guard and attached thereto [shield], a pair oflongitudinally spaced bars 110 and 111 are placed. The bars are solocated that the space between them is directly in line with thegrinding wheel as shown in Figure I. Said spaceis wide enough to permitthe passage therethrough of the knob on adjusting screw 85. When therests are in inoperative position, said bars prevent movement of alltoward the work except the one in line with the grinding wheel.

On top of cylinder 102 is a plate urged upwardly by' springs 121 againstadjustable stops in theforrn of headed screws 122. When piston 101 movesto bottom position, the portion 95 engages and depresses said platewhich in turn depresses a valve stem 125. As shown in Figure 4, stem 125is part of valve 126 slidably mounted in housing 127. A spring 128 holdsvalve 126 in closed f SINGLE CONTROL LEVER Most of the functions of thismachine are controlled positions of said lever for controlling saidfunctions are indicated on a guide plate 131 having a pair of parallel132 to slot 133 may be. prevented by blocking the' connecting slot 134.The means for doing this consists of a plunger 135 in a bore 136 in ahousing 137 which may.

or may not be integral with plate 131. Said 'plunger is actuated by apiston 138 slidably mounted'jin a cylinder 139 in housing137: Theportionof lunge-1135 adjacent piston 138 is reduced'in diameter so thaufl'uidunder constant pressure may jbe directed to' the rod end ofv cylinder139.

head of said cylinder. 7 I valve housing 127. When valve 126' is closed,fluid under the same pressure is directed'to both sides of piston 138.Because of the difierence in area of the opposite sides of said piston,it moves to the right so; that plunger 135 is projected into connectingslot 134. When valve 126 is opened, line is connected to exhaust line146. v Pressure on the head end of piston 138 is reduced to exhaustpressure. Restriction 143 prevents a similar reduction in pressure onthe rod end of said piston which thenmoves to the left, withdrawingplunger 135 from slot 134. The function of this lever 130 and plate 131is shown and described more in detail in said Patent No.

clamp operating position while the wheel is 'forv 'ard. When the wheelis moved back, the pressure on the piston is released and the plunger iswithdrawn by said spring.

Start switch and circuits operated by .vaid switch Fluid under constantpressure from line 1401's directed 5 through line 141 to the rod end ofc'ylinder 139 and through line 142, a restriction 143 and line'144 tothe Line 145 connects line 144 with 1 [initiating] the feed movementcertain conditions exist in the electrical and hydraulic circuits as aresult of operation of start switch 280. Furthermore, with the sizingdevice caliper in inoperative position, there is a complete restrictionof air flow; and the resulting pressure causes the mercury to close allfour size contacts. All relays are shown tie-energized. When energized,the arms move to the opposite position.

Closing start switch 280 completes a circuit through line 281 to oilpump relay 282, closing the contacts thereof and starting the oil pump150 and also slow feed oil pumps 300 and 301. These pumps are all drivenby the same motor. At the same time, said switch opens a normally closedcircuit to CRIS through contact 287 of CR16.

When CRIS is deenergized, current for all apparatus except the oil pumppasses through contact 418, closing contact 283 on oil pump relay 282(hereafter referred to as O. P.), and completes a circuit through lines284, 285, 420 and switch 410 to energize CR16 and open contact 287.Thus, the circuit to CRIS is also opened through said contact 287; andwhen start switch 280 is released to close the circuit through line 289to contact 287, said contact is open, and energization of CRIS isprevented.

Contact 283 through line 284 also acts through line 285 and normallyclosed contact 415 of CRIS and line 419 to contact 405 of O. I. and thusholds 0. P. after release of switch 280.

JET OPERATED PRESSURE SWITCH Normally closed contact 196 of jet pressureswitch 194 connects L1 and line 197 to energize relay CR4. Contact 261of CR4 acts through line 201 to energize the work rest solenoid and movevalve 183 to the left against spring 184. In this position said valveconnects line 185 leading to the lower end of work rest cylinder 102with exhaust line 186. CR4 is held through its contact 260, line 237 andthe normally closed contact 251 of CR5 and also through the normallyclosed contact 236 of gauge limit switch 235.

SIZE CONTROL An air operated sizing device of the type shown incopending application Serial No. 773,388, filed September 11, 1947, ismounted for movement toward and from operative relation with the work.It consists of a caliper element 230 having two fixed feelers and onemovable feeler 231. One end of the movable feeler engages an air valve232 and controls the flow of air in accordance with change in thediameter of the work piece. The change in air pressure is used to changethe level in a mercury U tube of the type shown in Patent No. 2,220,470,granted November 5, 1940, except that in this case there are fourcontacts instead of two. Rather than repeat the drawing of theabove-mentioned patent, we merely'indicate these contacts in theconventional manner in the wiring diagram and identify them by thenumerals 1, 2, 3 and 4. When the caliper 230 is in inoperative position,the movable feeler 231, not being restrained by the surface of a workpiece, permits air valve 232 to move to a closed position. Air pressureis thus built up in the mercury switch (not shown), and all fourcontacts remain closed until the caliper is placed on the work. Thenfeeler 231 is moved by contact with the work to open valve 232; and asthe pressure drops, all four contacts are opened.

Time delay relay 33S energized through #4 sizing device contact holdsnormally closed contact 334 open for a predetermined interval and thusprevents a complete circuit to any of the other sizing device contactsafter the caliper is returned to engagement with the work piece. anduntil the sizing device contacts are opened by the mercury column. Ifthese contacts were not tem- -porarily dead, 334 would permit a completecircuit from sizing contact #3 which would operate the reset valve andmove the wheel base to inoperative position instead of continuing thefeeding movement.

Movement of caliper 230 toward and from operative position is used toactuate a limit switch 235, the function of which will be describedlater.

NORMALLY CLOSED SIZING DEVICE CONTACTS While caliper 230 is out ofcontact with a work piece,

air pressure builds up in the mercury switch and closes all fourcontacts.

Contact #1 completes a circuit from L1 to one side of the slow feedsolenoid through line 330. Line 231 connects the other side of saidsolenoid through line 332 to normally closed contact 334 of delay relay335.

Contact #2 closes a circuit from L1 through lines 340 and 341 to CR6 andthrough lines 342, 331 and 332 to normally closed contact 334 of delayrelay 33S. Delay relay 335 is energized from contact #4. Thus, contact334 remains open and CR6 and the slow feed solenoid remain deenergized.

Line 340' fromcontact #2 leads to a normally open contact 351 of CR7.Line 340 is also connected to CR9 through line 233. The other side ofCR9 is connected to La through line 234.

Contact #3 connects L1 through line 360 to CR7 and through lines 361,331 and 332 to contact 3340f delay relay 33S. CR7 remains deenergizedbecause contact Before [bringing] the grinding wheel is brought forward,the work must be held securely by the clamping fixtures. So long asthere is no pressure on the clamping fixtures, pressure switch 380 has anormally closed contact 381 which completes a circuit from L1 throughline 382, contact 381 and lines 383 and 364 to energize CRIB. When CRIOis energized, its normally closed contact 370 is opened; and the circuitthrough line 372 to the reset solenoid is broken, deenergizing saidsolenoid and permitting spring 373 to shift valve to the right. In thisposition valve 374 directs fluid under pressure from lines 151 and 390through line 391 to the left end of feed control valve 153, thuspreventing the shifting of said valve to advance wheel 16 while the workclamps are open.

CLAMPS HYDRAULIC AND ELECT RIC CIRCUITS When valve 39Sis opened by lever130, fluid under pressure from line 390 may pass through lines 396 and397 to the work clamping fixtures 71 and 72. Said fluid also passesthrough line 398 to actuate pressure switch 380. When so actuated saidswitch opens contact 381, deenergizing CR10, closing contact 370 andenergizing the reset solenoid so that valve 374 moves to the left toconnect line 391 with exhaust, thus relieving pressure at the front endof valve 153. It also closes contact 384 which completes a circuit fromL: through line 385 and manually operated headstock starting limitswitch (not shown) to energize HF which starts motor 350. HP has anadditional normally open contact 386 which is closed at this time.Contacti386 connects L1 with one side of open contact 343 of CR6.

HYDRAULIC FEED RAPID Fluid under pressure is supplied to feed cylinder25 by a constant-volume pump 15!) through lines 151 and 152, reversingvalve 153 and line 154 at a pressure determined by relief valve 155.Fluid under pressure from relief valve 155 passes through line to valve161 at a pressure determined by relief valve 162.- Said valve 161 ispressure operated from right to left against a spring 163.

Fluid under pressure from line 151 is also directed through line to theslow feed solenoid valve 171 and. through line to valve 161. Said valvethus has two sources of fluid under pressure at two different pressures.Fluid at either pressure is directed through line 182 to work restsolenoid valve 183. The only piston 52.

reason for the high pressure is to move the work rest into positionrapidly. duces the impact of the rest against the stop 82 or the work.The low pressure is sufficient to support the work during grinding.-

Fluid from line 151 passes through a restriction 190 and through line191 to a nozzle 192 from which the fluid is discharged as a jet againstthe end of piston rod 27. When piston rod 27 approaches nozzle 192closely enough to reduce the flow therefrom, the resulting pressure actsthrough line 193 to actuate pressure operated switch 194.

GRINDING FEED Fluid under pressure for the pin grinding feed is suppliedby difierential pumps 300 and 301, the capacity of pump 300 beingslightly greater than that of pump 301 or it may be of. the samecapacity and operated at a slightly higher speed.

Pump 300 is connected through lines 302 and 303 to one end of feedcylinder 50 and through check valve 304 to line. 154 for exhaust. Line302 is connected by line 305 to fast feed valve 315. Pump 300 is alsoconnected through check valve 306 to the intake of pump 301. When valve315 is open to exhaust, that portion of the output of pump 300 not takenby pump 301 is discharged to. exhaust.

Pump 301 is connected through check valve 307, line 308 and line 309 tovalve 108, and line 310 back to the pump. Line 309 is extended to slowfeed valve 171. Line 170 connects valve 171 with high pressure line 151.Said pump 301 is also connected through check valve 312 to line 303.

So long as valves 108-and 171 are in the position shown, pump 301fwillreceive; its supply entirely from highpressure line 151 through valve171 and line 309.

' This higher pressure will hold check valve 307 closed. .Said pump willbe supplied from line 309 through valve 108 and line 3101 The highpressure in line 310 closes check valve 306 so that the entire output ofpump 300 passes through line 302 where it is added to the entire .outputof pumpf 30 1 and passes through check'valve' 312 so that the combinedoutput of both pumps acts on When valve 108' is shifted to the right,pump' 301 receives its entire supply from pump 300. The remaining outputof pump 300 passes through line 302 to line 303, while the outputof'pump 301 passes through check.

valve'312 to line 303 since check valve 307 is still held closed by thehigh pressure in line 309;.Although both pumps feed [pump] into line303, the volume passing through said line .is in effect the equivalentof the'output of pump 300 only. I

is shifted to exhaust posi- When slow feed valve 171 tion, the entireoutput of pump 301 .is exhausted through lines 308 and 309. Under .theseconditions the only fluid under pressure remaining to actuate piston 52is the small volume by which the output of pump 300 exceeds that of pump301.

SWITCH AND OVERLOAD SHUT OFF The entire machine may be stopped with thewheel MASTER sror base in inoperative position either by master stopswitch 400 or by overload relays 410. Fo'r'this purpose said step switchmay be connected to L1 through any or all of three circuits. I i

(a)' From stop switch 400 through. lines 285, 286,

- contact 287 of C1116, normally closed contact of start switch 280,contact 40s-of O. P line 419 contact 430 of TRX, wheelbase limit switch414, andcontact of (b) From stop that. 400 through lines zas, 284,contact 283 050. P. to L1. I w

The change to low pressure re base 15 moves to inoperative position,when said switch is released and the oil pump stops.

Closing stop switch 400 connects L1 through any of the above-mentionedpaths through line 401 to energize CRIS, opening contact 415 and closingcontacts 417 and 418.

Opening overload relays 410 will deenergize CR16, closing [normallyclosed] 287 and connecting L1 through normally closed switch 280, lines289 and 401 to energize CRIS.

Opening normally closed 415 breaks the circuit to start switch 280.Closing 417 holds CRIS through 283 of O. P. and lines 284 and 285.Closing 418 connects L1 from contact 405 of O. P. through line 406 andfrom 418 through line 383 to energize CR10 which deenergizes resetsolenoid, causing wheel base 15 to move to inoperative position and openswitch 414.

v ping lies in the fact that the oil pump 150 is kept in operation untilthe wheel has been moved away from the work and thus provides the motivepower for effecting the back off movement.

If for any reason the hydraulic system should fail through leakage orotherwise, the wheel base could not be moved-to inoperative position andthe machine would keep running. In order to insurethe shutting off ofthe machine, a timing relay TRX is placed in parallel with CRIS and thecontact 430 of TRX in series with the wheel base limit switch 414. Saidrelay will be energized simultaneously with CR15 and will function toopen the piston 138 in the left hand position.

same circuit or limit switch 414 at a predetermined time thereafter.

Operation known as the cheek, the rapid movement is reduced by dash pot31 to a speed suitable for cheek grinding which is efiected by the sidesof the wheel. The feeding movement continues at this rate until the flowof fluid from nozzle 192 is reduced or stopped by the end of piston rod27.

When valve 153 moves 'to the left, line 157 is connected to theexhaust'passage from said valve. This line is connected through line 158to the left end of valve 161. Line 157 is continued to the upper end ofcylinder 102 and through line 55 to the upper end of cylinder 50. Line157 is connected directly to the left end of feed cylinder 25.

When the upper end of cylinder 102 is connected to exhaust, the pressureon plate 120, Figure 4, is released and said plate, being then lifted bysprings 121, releases valve 126 which is then moved to closed positionby spring 128. Fluid under pressure from line due to restriction 143 hasbeen acting through line 141 to'hold With the closing of valve 126,fluid fron'rrestriction 143 builds up pressure in line 144 and againstthe head end of piston 138. Because of the, greater surface at the headend, said piston is moved to the right and plunger 135 blocks slot 134,lever 130 having been moved into slot 132 to actuate the work clampingfixtures and start rotation thereof before the initiation of saidfeeding movement.

Pressure built up in lines 191 and 193 as a result of blocking theescape of fluid from nozzle 192 actuat'es pressure switch 194 to closecontact 195 thereon and open contact 196. Opening contact 196 opens acircuit through line 197 to relay coil CR4 which is held through contact251 of CR5, contact 227 of CR12 which depends on normally closed timercontact 210 and normally closed gauge limit switch contact 236. Thus,the opening of contact 196 has no immediate effect on CR4.

Contact 195 directs current from line 1 through line 198 and thenormally closed contact 210 of timer clutch relay 211 to energize relayCR12. Contact 221 of said relay CR12 then completes a circuit throughline 222 to start timer motor 223.

Contact 224 of CR12 completes a circuit from contact 195 on pressureswitch 194 through line 225, [pin feed] limit switch 60 actuated by cam62 on handwheel 42, line 226, contact 240 of CR9 which is energizedthrough size device contact 2 so long as the caliper 230 is ininoperative position. The circuit is completed through line 242 to relayCR opening contact 251 and closing contact 252. Opening contact 251removes one source of energization to relay coil CR4 through line 237and holding circuit contact 260. However, the holding circuit is stillcompleted from L1 through the normally closed contact 236 of gauge limitswitch 235 and line 237. Said holding circuit is also maintained by thethird contact 227 of CR12. Said contact is connected through line 228 toline 237. Thus, caliper 230 may be made to engage the work at any time;but opening contact 236 thereby will not deenergize relay CR4 and thework rest solenoid until CR12 is deenergized, CR5 has been energized,and current cut 011 from all sources to relay CR4.

CR12 is not deenergized until timer 223 functions at the end of apredetermined period, beginning with the actuation of jet operatedpressure switch 194.

WORK REST The opening of contact 236 by movement of the gauge I limitswitch 235 in response to the positioning movement of caliper 230 toengage the work piece will deenergize relay CR4 if CR12 is alreadydeenergized, opening the circuit from L1 through contact 261 and line201 to deenergize the work rest solenoid. Spring 184 will then shiftvalve 183 to the right, connecting pressure line 182 from valve 161 toline 185, leading to the lower end of work rest cylinder 102, and movingpiston 101 rapidly upwardly so that work rest engaging member 95 mayengage and shift work rest 80 into operative relation with work piece70. It should be noted that fluid under pressure for operating the workrest at this time comes to valve 161 from pump 150 through high pressureline 151 and line 180. As piston 101 moves upwardly, it uncovers a portleading to line 107 which in turn is connected through line 164 to theright end of valve 161. Said valve then moves to the left against spring163 and changes the source of fluid from high pressure lines 151 to 180to low pressure line 160. Thus, the work rest is moved rapidly intoposition at high pressure and held in working position by a lowerpressure.

Line 107 also leads to the left end of a slow feed bypass valve 108,which will be described later in connection with associated elements.

The above operation of the work rest takes place only after theexpiration of the timed period. Prior to that time, contact 252 of relayCR5 completes another circuit from line 242 through line 243 to energizethe fast feed solenoid and shift valve 315 to the left against spring316.

When fast feed valve 315 is in this position, it blocks the exhaust offluid from line 305 and pumps 300. and 301. Since pump 301 is at thistime receiving its supply third feed rate.

from pump and lines 309 and 310 as described above, check valve 306 isheld closed by the higher pressure; and the total output of the twopumps 300 and 301 is directed to feed cylinder 50 to eifect a roughgrinding feed. This feed is for grinding the crank pins round. Thisfeeding movement continues until cam 62 on handwheel 42 actuates limitswitch 60. Opening one contact of switch 60 deenergizes CR5, closing 251and opening 252. Closing the other contact of switch 60 energizes thetimer clutch to start the timed period.

Opening 252 deenergizes the fast feed solenoid, and valve 315 is shiftedto open line 305 to exhaust thus bypassing the output of pumps 300 and301 to stop a rough feed movement of feed piston 52.

Feed is resumed after the period for which timer 223 is set, but only ifcaliper 230 is in engagement with the work piece. Operation of the timeropens contact 210 and closes 212. Moving the caliper intoengagement withthe work opens contacts 236 and closes 238.

Opening timer contact 210 deenergizes CR12 to stop the timer 223.Closing contact 212 closes a circuit from L1 through line 198 to contact238 of gauge limit switch 235.

Closing contact 238 energizes CR5 which closes 252 to energize fast feedsolenoid and shift valve 315 to cut off exhaust from line 305.

All circuits to CR4 are opened, including contacts 236 of gauge limitswitch 235, 227 of CR12 and 251 of CR5.

Shifting valve 108 to the right cuts off the supply of high pressurefluid from line 309 to pump 301. Pump 301 then pumps from pump 300through check valve 306 and from the pump through check valve 312 toline 303. Pump 300 pumps through line 302 an amount equal to thedifference in capacity of the two pumps. This provides a second feedrate for a rough grinding operation for 'quick reduction to approximatefinished size.

Feed continues at second rate until work size causes first contact ofthe sizing device to function.

#1 sizing device contact energizes the slow feed solenoid to shift valve171 to change line 309 from high pressure to exhaust so that the outputof pump 301 passes through check valve 307 to exhaust, leaving only thesmall volume which is the difference between the capacities of the twopumps to continue driving feed piston 52 at a This feed rate is for afinish grinding operation.

As the work is reduced in size, sizing device contact #2 energizes CR6through lines 340 and 341 and CR9 through lines 340 and 233. CR6 is heldthrough contact 386 of H. F. CR9 opens 240 to deenergize CR5. Sizingdevice contact #2 also prepares a holding circuit for CR7 when CR7 isenergized by sizing device contact #3.

When CR5 is deenergized, it opens contact 252 to deenergize the fastfeed valve 315 to exhaust pumps 300 and 301 to stop the feed movement ofpiston 52.

After the feed movement stops, the grinding wheel remains in contactwith the work to effect a polishing operation which includes a slightadditional removal of stock, the extent of which is determined by sizingdevice contact.#3.

When sizing device contact #3 is closed, it energizes CR7 closingcontacts 351 and 352. 351 provides a holding circuit which includessizing device #2. 352 energizes CR10 which completes circuits tonormally closed 381 of hydraulic clamp limit switch 380. CR10, whenenergized, opens contact 370 to deenergize the reset solenoid. Spring373 shifts valve 374 to connect high pressure line 390 from 151 to 391to shift valve 153 to reset position. In this position of valve 153,fluid under pressure is directed to effect a reversal of feed pistons 26and 52 and work rest piston 101 to return them to starting position.

We claim:

1. A grinding machine including a bed, a work support and a grindingwheel support slidably mounted thereon for movement toward and from saidwork support, means for successively supporting a series of spacedportions on a work piece during a grinding operation including aseparate steady rest for each portion, means for moving each of saidrests into operative position when the corresponding work portion is inposition to be ground, a calipering device movable toward and fromoperative position relative to the portion to be ground and meansresponsive to movement of the calipering device into operative positionfor causing said moving means to move the steady rest corresponding tothe portion being ground to move into work supporting position.

2. A grinding machine including a bed, a work support and a grindingwheel support slidably mounted thereon, a grinding wheel rotatablymounted in said support, said work support being slidably mounted formovement longitudinally relative to said grinding wheel, means on saidwork support for successively supporting a series of spaced portions ona work piece including a separate steady rest for each portion and asingle hydraulic motor mounted on the bed substantially in alignmentwith the grinding wheel for moving the proper steady rest intooperativerelation with the work. 1

3. A grinding machine including a bed, a work support and a grindingwheel support slidably mounted thereon, said work support being slidablymounted for movement longitudinally relative to said grinding wheel,means for successively supporting a series of spaced portions on a workpiece during a grinding operation including a separate steady rest foreach portion, means for efiecting said longitudinal movementintermittently to position said portions in operative relation with saidgrinding wheel, and means including a common motor for causing thesteady restcorresponding to the portion being ground to move into worksupporting position.

4. In a grinding machine, a bed, a grinding wheel support slidablymounted thereon, a work support slidably mounted thereon, means toefiect a relative longitudinal movement of said supports forsuccessively placing a series of axially spaced portions on a work piecein operative relation with said grinding wheel, a plurality of steadyrest members on said work support in fixed ax'ial relation to saidspaced portions and a single work restactuating device in fixed axialrelation with said grinding wheel for actuating the'rest correspondingto the work portion which is in operative relation with the grindingwheel.

5. A grinding machine, a bed,'a grinding wheel support slidably mountedthereon, a work support slidably mounted thereon for longitudinalmovement relative to said wheel support for successively placing aseries of axially spaced portions on a work piece in operative relationwith said grinding wheel, a plurality of steady restmembers on said worksupport infixed axial relation to said spaced portions and means to'holdall of said rests in inoperative position except the one in front of thegrinding wheel including an'obstruction'in the path of each 'of.saidinoperative rests. 1

6. In a grinding machine, a bed, a grinding-wheel support slidablymounted thereon, a work support slidably mounted'thereon, means toeffect a relative longitudinalmovement'of said supports for successivelyplacing a series of axially spaced'portions on a work piece in operativerelation with said grinding wheel, a plurality of steady restmembers-Hon saidwork support'in fixed axial relation to saidspaced-portions and'mean's to prevent movement of any of said restsexcept the one in front of the grinding wheel including al'pair oflongitudinally fixed bars positioned to obstruct movement of said rests,said bars being longitudinally spaced to permit one rest to be moved tooperative position;

'7. A grinding machine including a bed, a work support eration includinga separate steady rest for each portion,

a single actuating means for steady rests, a timing mechanism and meansfor starting same at a predetermined point in the grinding operation,and means actuated by said timer for causing said actuating means tomove the steady rest corresponding to the portion being ground into worksupporting position.

8. A grinding machine including a bed, a work support and a grindingwheel support slidably mounted thereon for movement toward and from saidwork support, means on said work support for successively supporting aseries of spaced portions on a work piece during a grinding op erationincluding a separate steady rest for each portion, a single actuatingmeans for said steady rests, a calipering device movable toward and fromoperative position relative to the portion to be ground, a timingmechanism and means for starting same at a predetermined point in thegrinding operation and means actuated by said timer in cooperation withthe movement of said calipering device, for causing said actuatingmeansto move the steady rest corresponding to the portion being ground'intowork supporting position.-

9. A grinding machine including a bed, awork support and' a grindingwheel support slidably mounted thereon for movement toward'and from saidwork support, means for successively supporting a series ofspacedportions on a work piece during a grinding operation including a sepanda grinding wheel support slidably mountedthereon for movement toward andfrom said work support, means on said worksupport for successivelysupporting a series. of spaced portions on 'a work piece during agrinding oparate steady rest for each portion, a calipering devicemovable toward and from operative position relative to the portion to beground, atiming mechanism and means for starting same at a predeterminedpoint in'the grinding op eration and means actuated by said timer incooperation with the movement of said calipering device for moving saidgrinding wheel support.

10. In a machine tool, a plurality of steady rests, one for each of aseries of spaced portions of a work piece, each rest comprising a basemember, a work engaging and supporting member movably mounted thereonfor move ment toward and from operative position, a positive stop in thepath of movement of said work engaging member for locating said memberin finished. size position,'power means including a motor common to allsupports for suc-' cessively moving each ofsaid support members towardand from its respective stop and means for adjusting each of said workengaging members separately to the finished size of. the particularportion to. be supported.

.11. In a machine tool, a plurality of steady rests, one

for each of a series of spaced portions of a work piece,

each rest comprising abase member, a work engaging and supporting membermovablymounted thereon for movement'toward and from operative position,a positive'stop in the path of movement 'of work engaging memberfor-locatingsaid member in size position, power m ans c mmend- 11Ppqrtsrm ins aid s ppo t, member in the direction. of'said stop, meansto actuate said power-meansfir'st with fluid under a given and meansoperable as-said rest'engag'es the work to switch ting 0.01, movabletoward and away iromisaid-work sup- 0 port, power means' forflactuatingsaid clamping'mcans' and said cutting toolpn main power supplytorthejmachine; master control. means for stopping said machine includingmeans for controlling the power means tor said cutting tool to move saidtool toinoperativepositiom-andad ditional control; actuated. by saidi:n.ove1 nent of s r rt,

13 1 said cutting tool for delaying the stopping of said main powersupply until said tool is withdrawn.

14. In a metal working machine, a work support, means for clamping awork piece in said support, at out ting tool movable toward and awayfrom said work support, power means for actuating said cutting tool,additional power operated mechanisms in said machine including workdrive means, hydraulic pumps, and tool rotating means, a main powersupply for the machine, master control means actuated either manually orunder certain predetermined conditions by any of said power operatedmechanisms for stopping all of said mechanisms except said pumpincluding means for controlling the power means for said cutting tool tomove said tool to inoperative position, and additional control meansactuated in response to said movement of said cutting tool for cuttingoff said main power supply.

15. In a metal working machine, a work carriage, means for rotatablysupporting a work piece thereon, a cutting tool movable toward and awayfrom said work support, power means for actuating said Work supportingmeans and said cutting toolincluding a motor-driven pump and hydraulicmotor for said supporting means and said cutting tool, means including avalve operable upon failure of said work supporting means to supportsaid work piece, to direct fluid to move said cutting tool toinoperative position.

16. In a machine tool, a bed, a work support, a tool support and asteady rest' all movably mounted on said bed, means for causing relativetransverse and longitudinal movements between said work support, andsaid steady rest and tool support, a control lever for said movementsand means to prevent operation of said control lever to cause saidlongitudinal movement while said tool and said steady rest are inoperative position including a plunger for limiting the movement of saidlever, and means operable upon withdrawal of said steady rest forwithdrawing said plunger to inoperative position.

17. In a grinding machine, a work support, a wheel support, a grindingwheel rotatably mounted thereon, means to efiect relative transversemovement between said supports including a hydraulic motor and pumps forsupplying fluid under pressure for operating said motor, a back rest forsupporting a work piece during a grinding operation, means forperforming a part'of said grinding operation without the back rest andmeans operable upon movement of said rest into operative position forchanging the rate of said transverse movement to a slower rate.

18. In a grinding machine, a work support, a wheel support, a grindingwheel rotatably mounted thereon, means to efiect'relative transversemovement between said supports including a hydraulic motor and pumps forsupplying fluid under pressure for operating said motor, a plurality ofoutlets from each of said pumps, check valves in some of said outlets,means for applying a higher pressure to hold said check valves closedand means operable in response to change in size of a work piece fordiverting said higher pressure and-permitting fluid to pass throughcertain of saidcheck valves whereby to adjust the combined output ofsaid pumps.

19. A machine for grinding axially spaced portions on a work pieceincluding a bed, a work support slidably mounted on said bed, a grindingwheel support slidably mounted on said bed for movement toward and awayfrom said work support, means for eflecting movement of said grindingwheel support toward said work support at a rapid rate, means forreducing said rapid movement to a movement suitable for efiecting arough grinding operation, means separate from said rapid feed means forf etfecting said movement at a slow feed rate, a timing "mechanism,means for stopping said rough grinding movement of the wheel support andstarting said timer to permit a grinding operation without feed for apredetermined interval, a caliper device movable toward and fromoperative position relative to the portion to be ground, and meansactuated jointly by movement ofsaid caliper and said timer to workengaging position at the end of said predetermined interval for[initiating] resuming operation of said slow feed means.

20. A grinding machine including a bed, a'work support and a grindingwheel support slidably mounted thereon for movement toward and from saidwork support, a calipering device-movable toward and from operativeposition relative to the portion to be ground, a timing mechanism andmeans for starting same at a predetermined point in the grindingoperation, and means actuated by said timer in cooperation with themovement of said calipering device into work engaging position forinitiating movement of said grinding wheel support.

5Z1. In a metal working machine, a work support, a cutting tool movabletoward and away from said work support, power means for actuating saidcutting tool, ad-

ditional power-operated means including a work drive mechanism andhydraulic pumps, a main power supply for the machine, master controlmeans actuated either manually or in response to failure of any of saidpoweroperated mechanisms to function properly for stopping said machine,including means for controlling the power means for said cutting tool tostop all of said power-operated mechanisms except said pump, said pumpserving to supply fluid to move said tool to inoperative position, andadditional control means actuated in response to said movement of saidcutting tool for stopping said pump.

22. In a crank grinding machine, a bed, a grinding wheel supportslidably mounted thereon, a grinding wheel rotatably mounted in saidsupport, means for eifecting a rapid feeding movement of said grindingwheel support to place said grinding wheel in operative position, meansto reduce said rapid feeding movement to a feed suitable to grind theside walls of a crankpin, means operable at the end of the rapid feedmovement for initiating a slower feed movement for truing the crankpin,means for stopping said truing feed after a predetermined movement whilecontinuing the grinding operation until stress in the crank is relieved,a caliper mounted for movement toward and away from operative engagementwith the work, means for resuming said feeding movement after' apredetermined interval and at a slower rate, providing said caliper hasbeen moved tooperative position, means for effecting successivereductions in the feed -rate in response to a change in size of the workuntil a predetermined size is reached which is just short of thefinished size, and means to continue the grinding operation without feeduntil finish size is reached. 23. In a grinding machine, a work support,a wheel support, a grinding wheel rotatably mounted thereon, means toefiect relative transverse movement between said supports including ahydraulic motor and difierential pumps for supplying fluid underpressure for operating said motor, a back rest movably mounted on thework support for supporting a work piece during a grinding operation anda hydraulic motor for moving said rest, means for temporarily stoppingsaid transverse movement of said rest into operative position forchanging the rate of said transverse movement to a slower rate includinga pressure operated valve, actuated at a predeter mined point in themovement of said back rest for changing the connections between saidpumps and said hydraulic motor.

24. In a grinding machine, a work support, a.,wheel support, a grindingwheel rotatably mounted thereon,

means to effect relative transverse movement between said supportsincluding a hydraulic motor and differential pumps for supplying fluidunder pressure for operating said motor, a back rest movably mounted onthe work support for supporting a work piece during a grinding operationand a hydraulic motor for moving same, means for temporarily stoppingsaid transverse movement with said back rest in inoperative position,and means including a pressure operated valve operable in response tomovement of said rest into operative position for changing the rate ofsaid transverse movement to a slower rate, and connections between saidvalve and said back rest for actuating said valve to change the flow offluid between said pumps and said hydraulic motor.

25. In a grinding machine, a work support, a wheel support, a grindingwheel rotatably mounted thereon,

means for effecting relative transverse movement between said supportsincluding a hydraulic l'notor, differential pumps for supplying fluidunder pressure for operating said motor, a pressure operated valve forcontrolling the supply of fluid from said pumps to said motor, a backrest for supporting the work piece during the grinding operation, apiston and cylinder foractuating .said back rest and means for actuatingsaid pressure operated valve at a predetermined point in the movement ofsaid back rest, comprising a fluid conduit connecting said back restcylinder and said valve.

26. A machine including a bed, a'work support slidably mounted on saidbed, a grinding wheel support slidably mounted on said bed for movementtoward and away from said work support, means for eflecting movement ofsaid grinding wheel support toward said work support at a rapid rate,means for reducing said rapid movement to a movement suitable forefiectin'g a rough grinding operation, means separate from saidrapidfeed means for efi'ecting said movement at a slow feed rate, a timingmechanism, means for automatically stopping said rough grinding movementof the wheel support and starting said timing mechanism to permit agrinding operation without feed for a predetermined interval, andmeansactuated by said timing mechanism-at the end of said predeterminedinterval for resuming operation of said slow feed means for a finishgrinding operation.

27. In' a. grinding machine, a-bed, a grinding wheel I support slidablymounted thereon, a grinding wheel rotatably mounted in said support,means for efiecting a rapid feeding movement of said grinding wheelsupport to place slower feed movement for truing the workpiece, meansfor automatically stopping said truing feed after a predeterminedmovement while continuing the grinding operation unti s stress in thework is relieved, and means for automatically resuming said feedingmovement after a predetermined interval and at a predetermined rate.

28. In a grinding machine, a bed, a grinding wheel support slidablymounted thereon, a grinding wheel rotatably mounted in said support, awork support'on said bed, means for rotatably supporting a workpiecethereon,

means for efiecting a relative feeding movement between said supports toperform a rough grinding operation for truing the workpiece, means forautomatically-stopping said truing feed after a predetermined-movementwhile continuing the grinding operation until stress in the workpiece isrelieved and means for automatically resuming said feeding movementaftera predetermined interval.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 1,045,876 Norton Dec. 3, 1912 1,925,911 SteinerSept. 5, 1933 2,102,518 Johnson Dec. 14, 1937 2,141,596 Crompton Dec.27, 1938 2,167,311 Postma 'Ju1y 25, 1939 7 2,267,391 Astrowski Dec. 23,-1941 2,297,654 Johnson Sept. 29, .1942 2,322,727 Cole June 22, 1 943.-2,375,737 Silven May 8, 1945 2,419,133 Garside Apr. 15, 1947 2,435,059Thompson Jan. 27, 1948 2,478,562 Bin'ns I w 'Aug 9,1949- 'FOREIGN PATH I371,425 Great Britain.- Apr. 19,1932 I 523,199

Great Britain 2 Iuly9; 1940

